[Just realized I posted this information at Iowa GenWeb in 2012, but nowhere on my blog or website. So:]
If there are any LaBrune researchers listening, please let me know if you have any information that might support or refute an hypothesis I'm working on.
What I think I know:
(1) Philip and Ann LaBrune and family were in Clermont Co., Ohio in 1840. Jean-Baptiste was born there after the census. In 1850, the family was in Dubuque co., Iowa. Comparing the 1840 and 1850 censuses, a 20-25 yr old boy and a 10-15 yr old girl are not with the family in Dubuque. (These are the ages they would have in 1850.) Did they stay behind? Did they die? Were they not members of the family, but just living with them in Ohio? I don't know, but I have looked around to see if there are any LaBrunes back in southern Ohio.
(2) We don't know what happened to Philip. He is in the 1860 census. He is listed in an 1865 property tax roll. He is not in Dubuque in the 1870 census. He is not buried with his wife and the other LaBrunes. I have not researched extensively myself, but know of no death records for Philip. As an interesting, a little surprising, side note: Daniel Dooley, a neighbor and father-in-law to Philip & Ann's son, Jean-Baptiste, is buried next to Ann. Ann died in January 1868.
(3) In Oct 1868, a Philip LaBrune married a Josephine Oligée in Brown co., Ohio, a county adjacent to Clermont co., where the LaBrunes lived in 1840. Thinking this might be the missing LaBrune son, who possibly stayed behind, I dug deeper. I found Philip and Josephine in the 1880 census. They were both born in France: he in 1796; she in 1804. This Philip is about the same age our Philip who disappeared from Dubuque. Could it be?
Putting together the pieces:
As I said, the last record I have of Philip in Dubuque is a tax roll in 1865. If he did not die there, I assume he would have remained with his wife, Ann, while she was living. She died in Jan 1868, about 9 months before the marriage in Ohio. Perhaps after the death of his wife, he went back to the Clermont/Brown co. area of Ohio for something. Maybe that's why when Daniel Dooley died a year later, in 1869, the LaBrune family allowed him to be buried in "Philip's plot", since Philip had moved away and remarried. Maybe that's why there is no record of Philip's death in Iowa - he didn't die there?
Why would Philip go back to Ohio? I haven't found other LaBrunes there, so I'm giving up on finding the missing son. But what about the daughter? She could have been 5 in 1840 (listed as female under 5 at the time of the census). The first record I'm aware of in Iowa is the 1850 census, so the LaBrunes could have left Ohio as late as 1850. The missing daughter could have been as old as 15 years old when they moved. Still kind of young. I've gone back and looked at the 1860 census of the Oligée family in Brown co., Ohio. Josephine was married to an older Jacob Oligée and had several sons. The three that I saw were all married, and their wives were 20 to 25 years old, the age range of the missing LaBrune daughter.
I think the missing LaBrune daughter being married to one of the Oligée boys is a stretch. But I think there's a good chance that our Dubuque Philip moved back to Ohio and remarried. The age, the name, the location, the timing, and the lack of other LaBrunes in that area prior to the 1868 marriage are an awful lot of coincidences. I don't spend alot of time on my genealogy, but I'd like to dig up more information to either support or shoot down this theory.